Investigation on Eu3+ doped Sr2MgSi2O7 red-emitting phosphors for white-light-emitting diodes

The high-temperature solid-state synthesis of red phosphors Sr2MgSi2O7:Eu3+ with various Eu3+ concentrations is reported. Their luminescent properties at room temperature were investigated. XRD patterns indicated that the red phosphor powders conformed to the tetragonal Sr2MgSi2O7. An impurity structure appeared when > 20% Eu3+ was added. The samples showed a strong emission line at 615 nm and the intensity increased with increasing Eu3+ concentration until concentration quenching occurred. Charge compensation assisted in the reduction of the impurity structure and vacancies and enhanced the luminescent intensity. The decay measurements indicated that the lifetime of Eu3+ emission is about 2-3 ms. Some of the Eu3+ can be reduced to Eu2+ which is also discussed.